1H NMR titration and quantum calculation for the inclusion complexes of cis-cyclooctene, cis, cis-1, 3-cyclooctadiene and cis, cis-1, 5-cyclooctadiene with β-cyclodextrin

Author(s):  
Cao Yujuan ◽  
Lu Runhua
Author(s):  
Divya Singhal ◽  
Neha Gupta ◽  
Ashok Kumar Singh

4-(thiazol-2-yldiazenyl)phenol (L1) and 2-((4-hydroxyphenyl) diazenyl)-5-nitrophenol (L2) based on azo phenol were synthesised and used as selective colorimetric sensor for CN- and AcO− ion in DMSO/H2O-HEPES (v/v; 1:1, pH–7.3 ± 0.2) and showed good sensitivity with large red shifts and nanomolar detection limit for CN- and AcO- ion. The stoichiometry of L1 with CN−/AcO− ion was found to be 1:1 and L2 with CN−/AcO− ion was found to be 1:2. Binding constant for L1+ CN−, L1 + AcO−, L2 + CN− and L2 + AcO− were calculated by B-H plot as 1.6 × 103, 8.0 × 102, 8.4 × 103 and 1.7 × 102 respectively. L2 showed high selectivity towards CN− ion with low detection limit of 81 nM and large binding constant. In addition, 1H NMR titration and DFT studies also supported the deprotonation mechanism of receptors in the presence of selective anions.


Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6392
Author(s):  
Donghwan Choe ◽  
Cheal Kim

A novel acylhydrazone-based fluorescent sensor NATB was designed and synthesized for consecutive sensing of Al3+ and H2PO4−. NATB displayed fluorometric sensing to Al3+ and could sequentially detect H2PO4− by fluorescence quenching. The limits of detection for Al3+ and H2PO4− were determined to be 0.83 and 1.7 μM, respectively. The binding ratios of NATB to Al3+ and NATB-Al3+ to H2PO4− were found to be 1:1. The sequential recognition of Al3+ and H2PO4− by NATB could be repeated consecutively. In addition, the practicality of NATB was confirmed with the application of test strips. The sensing mechanisms of Al3+ and H2PO4− by NATB were investigated through fluorescence and UV–Visible spectroscopy, Job plot, ESI-MS, 1H NMR titration, and DFT calculations.


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